Return to the CurtPalme.com main site CurtPalme.com Home Theater Forum
A forum with a sense of fun and community for Home Theater enthusiasts!
Products for Sale ] [ FAQ: Hooking it all up ] [ CRT Primer/FAQ ] [ Best/Worst CRT Projectors List ] [ Setup Tips & Manuals ] [ Advanced Procedures ] [ Newsletters ]

 
Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist  Photo AlbumsPhoto Albums  RegisterRegister 
 MembershipClub Membership   ProfileProfile   Private MessagesPrivate Messages   Log inLog in 
Blu-ray disc release list and must-have titles. Buy the latest and best Blu-ray titles to show off in your home theater!

LG M4715CG / M4715CCBA back lite but no picture
Goto page 1, 2  Next
 
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Direct View Televisions and Monitors
View previous topic :: View next topic  
Author Message
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Thu Apr 23, 2015 5:42 pm    Post subject: LG M4715CG / M4715CCBA back lite but no picture Reply with quote


        Register to remove this ad. It's free!
Hello all. Found one of these LCD industrial monitors. Ran the PC into it, PC sent 1080p, screen backlight is on just the ocasional flickering across the top of the screen then the middle of the screen.

I have it open,

Any common areas to look at?

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sat Apr 25, 2015 7:16 pm    Post subject: Reply with quote

Anyone?
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sat Apr 25, 2015 7:54 pm    Post subject: Reply with quote

Got a picture via S-video. Full screen sttic but that's more then what VGA gave me.

It actually went clear for a second too!
There's a 6" wide bright bar on the right side of the screen about 10" out too. Video is displayed but it's a brighter band. Stationary, not rolling like hum bars, and vertical not horizontal.

Just noticed the picture within the band is color inverted (negative) and shifted down by 1/4 inch

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sat Apr 25, 2015 8:46 pm    Post subject: Reply with quote

And now the right half of the screen is blank...
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
winny




Joined: 09 Oct 2013
Posts: 403
Location: Sweden

TV/Projector: BD808s, BG1209/2


PostLink    Posted: Sun Apr 26, 2015 7:12 pm    Post subject: Reply with quote

Store it until you can find another one identical, swap the hopefully working video boards/LCD-drivers from it and have one working? Service manual? Toss it?
_________________
Melifluonze wrote:
Digital is easy. This is torture, but far more interesting...
Back to top
Curt Palme
CRT Tech



Joined: 08 Mar 2006
Posts: 24296
Location: Langley, BC

TV/Projector: All of them!


PostLink    Posted: Mon Apr 27, 2015 2:25 pm    Post subject: Reply with quote

Bad T con board or bad system board would be my guess.
Back to top
winny




Joined: 09 Oct 2013
Posts: 403
Location: Sweden

TV/Projector: BD808s, BG1209/2


PostLink    Posted: Mon Apr 27, 2015 2:28 pm    Post subject: Reply with quote

Remelt all solder joints in the oven? Nothing to loose?

http://hardforum.com/showpost.php?p=1035104340&postcount=648

_________________
Melifluonze wrote:
Digital is easy. This is torture, but far more interesting...
Back to top
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Mon Apr 27, 2015 5:02 pm    Post subject: Reply with quote

winny wrote:
Remelt all solder joints in the oven? Nothing to loose?

http://hardforum.com/showpost.php?p=1035104340&postcount=648


Interesting! Tha sure saves time soldering!

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Mon Apr 27, 2015 5:03 pm    Post subject: Reply with quote

Curt Palme wrote:
Bad T con board or bad system board would be my guess.


Any way to test, or do I just start replacing boards?

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Wed Apr 29, 2015 9:18 pm    Post subject: Reply with quote

Found the T-CON board on ebay: LG M4715CG CONTROL BOARD 6870C-0364B
http://www.ebay.com/itm/LG-M4715CG-CONTROL-BOARD-6870C-0364B-/171291116225?pt=LH_DefaultDomain_0&hash=item27e1bf02c1

Mine is an older version, slightly different layout. BUT it says from the same model TV. Do you think it will work?

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
Curt Palme
CRT Tech



Joined: 08 Mar 2006
Posts: 24296
Location: Langley, BC

TV/Projector: All of them!


PostLink    Posted: Wed Apr 29, 2015 9:26 pm    Post subject: Reply with quote

It's possible, but it's common for production runs to change, so all you can do is try it. Did you check the 2 amp SMT fuse on the orignal board? Those can blow open for no reason, giving the exact symptom you describe.

<edit> never mind on the fuse, you did get a pix with Svideo. Not the fuse.

If the small print part numbers match up, you're OK. if not, they won't work.
Back to top
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Wed Apr 29, 2015 9:42 pm    Post subject: Reply with quote

Here they are. Slightly different numbers. The eBay part is newer:
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
Curt Palme
CRT Tech



Joined: 08 Mar 2006
Posts: 24296
Location: Langley, BC

TV/Projector: All of them!


PostLink    Posted: Wed Apr 29, 2015 10:02 pm    Post subject: Reply with quote

I'll bet they won't work. Made that mistake a few times. You'll probably get a pix, but it may have lines, be pixellated, etc.
Back to top
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Thu Apr 30, 2015 4:34 pm    Post subject: Reply with quote

Another one just showed up with the right part number for $16.50 and free shipping. Time to roll the bones...

http://www.ebay.com/itm/121520703977

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sat May 30, 2015 7:35 pm    Post subject: Reply with quote

Tried this but no go. Still have the screen band and the right half of the screen is blank. Maybe one of the LCD driver boards or input board?

I can't even get a picture with s-video now.

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Fri Jun 12, 2015 2:48 am    Post subject: Reply with quote

AnalogRocks wrote:
Tried this but no go. Still have the screen band and the right half of the screen is blank. Maybe one of the LCD driver boards or input board?

I can't even get a picture with s-video now.


On these LCD's are there separate boards for the left and right sides of the screen?

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Wed Jul 22, 2015 8:00 pm    Post subject: Reply with quote

Which Caigs Deoxit version should I order to clean this TV? It has an intermittent connection and was left out in the rain making for some dirty connections.
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sun Aug 30, 2015 6:29 pm    Post subject: Reply with quote

Tried the new T-con board, got no picture. I have it open and I'll be cleaning things with Caig's. I may just swap back to the other board to see if I can get it to go.
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
Jeremy112




Joined: 28 Sep 2006
Posts: 2645
Location: Fond du Lac, WI


PostLink    Posted: Sun Aug 30, 2015 9:36 pm    Post subject: Reply with quote

You have to remember with LCD displays that the possibility exists that the LCD panel itself is toast. The only boards directly on the LCD panel are likely a couple PCBs that the T-CON board connects to, those could very likely have failed.
_________________
When I'm asking for a Model number, that doesn't mean I'm asking for a nude photo with your number on it Wink
Back to top
AnalogRocks
Forum Moderator



Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Tue Sep 01, 2015 6:33 am    Post subject: Reply with quote

I had a picture with this one via S-video. I think the input board may be fugged.

I cleaned all the contacts with Caigs. The power and back light will stay on now. So one step closer Thumbs Up

_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
Display posts from previous:   
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Direct View Televisions and Monitors All times are GMT
Goto page 1, 2  Next
Page 1 of 2
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum